1. Field of the Invention
The present invention relates generally to a method of determining the authenticity of packaged products and, specifically, to the detection and analysis of radiation emitted by fluorescent materials to determine whether or not a packaged product is authentic.
2. Background of the Invention
Throughout history, extensive efforts have been undertaken in attempts to ensure that certain valuable documents and objects were genuine. Measures employed have ranged from wax seals impressed with the signets of monarchs to, in more recent times, devices such as holograms, water marks, microreplicated patterns, and the like. Especially with respect to documents such as negotiable instruments, numerous measures involving printing techniques, special inks and/or dyes, fluorescent materials, and the like have been employed. For a succinct overview of such measures, the reader is directed to the Background of the Invention section of U.S. Pat. No. 5,644,352 (Chang et al.), as well as the documents cited therein.
Relatively recently, products displayed and sold from store shelves have become of more interest to counterfeiters. One class of such valuable, yet easily duplicated products is computer software. Much time, energy, and intellect is expended in creating such products, yet a counterfeiter can reproduce such products in a short amount of time and without expending much effort or money. Accordingly, anti-counterfeit measures have become of great interest to developers and manufacturers of products such as computer software.
One of the first measures employed in efforts to thwart counterfeiters involved holograms; however, after a relatively short amount of time, counterfeiters were able to reproduce such holograms with relative ease. More recently, microreplicated patterns have been employed. While these are much harder to produce, one wishing to verify the authenticity of a product on a store shelf needs to inspect each product individually. This type of inspection often can be slow and labor intensive. Further, microreplicated patterns can involve additional costs because the authenticity feature is not incorporated into an existing part of the packaged product in question.
Retail products such as computer software often come packaged in a paperboard box sealed in a thermoplastic film. Because the type of film used to wrap such packages often is relatively simple (e.g., a single-layer polyethylene film), counterfeiters have little problem finding converters who can take polymeric resin(s), make simple films, and seal the film around the counterfeit product made by the counterfeiter.
Some have suggested that incorporating photoluminescent materials (e.g., phosphorescers and fluourescers) into packaging materials might provide an easily verifiable authenticating feature useful with regard to retail products. However, as with holograms, this type of authentication is not difficult to reproduce once the counterfeiter is aware of the presence of a photoluminescer and identifies the particular material used. Despite this potential limitation, efforts to make authentication through the use of photoluminescent materials a viable alternative continue.
A type of photoluminescent authentication is described in U.S. Pat. No. 5,005,873 (West). That reference teaches incorporating two photoluminescent materials into a film which can be laminated on a substrate such as, for example, a credit card. The laminated substrate is authenticated by exposing it to a wavelength of ultraviolet (UV) light and visually inspecting the color of visible light emitted by the photoluminescent material. Once the first inspection is complete, the laminated substrate is exposed to a different wavelength of UV light and again visually inspected to determine whether a second, different color is emitted. (Although fluorescence is referenced as the applicable emission phenomenon throughout this reference, the fact that the photoluminescent emission occurs in the visible portion of the spectrum as well as the length of time that emission is said to occur, i.e., sufficiently long to allow for visual inspection, both seem to indicate that the process involved is phosphorescence rather than fluorescence.) However, the sequential irradiation-inspection taught by this reference does not seem capable of being adapted into an easily repeatable, perhaps automated, authentication technique.
Although not concerned with the authentication of documents or retail products, U.S. Pat. No. 5,201,921 (Lutterman et al.) and U.S. Pat. No. 5,329,127 (Becker et al.) both teach the incorporation of fluorescent materials into plastic materials. Both patents are concerned with a method of labeling different plastics so that the materials can be identified and separated automatically for purposes of recycling. The former teaches the incorporation of 0.005 to 10 parts per million (ppm) of a fluorescent marker into a plastic material. By designating a particular fluorescent material to a given type of plastic material, one can automate a process for separating a variety of plastic materials for recycling purposes by, for example, exposing the plastic materials to radiation that includes wavelengths that excite the fluorescent materials, looking for a given wavelength of emitted radiation, and selecting the plastic materials with the emitted the particular wavelength of interest. The latter patent expands on this recycling automation idea by teaching the incorporation of a plurality of fluorescent materials into each plastic material, then confirming/rejecting a particular material based on the combined emission spectrum it produces when exposed to excitation radiation. The use of a plurality of fluorescers is said to overcome the relatively limited number of available dyes. After exposing a plastic material to a single radiation source, the excited component fluorescent materials emit for different lengths of time. This difference in emission duration is used to distinguish the fluorescent materials and to identify the plastic material in which they are located.
That which has not been described previously, and remains highly desirable to the manufacturers of valuable retail products such as computer software, is a method of packaging such products so that they include one or more markers that can be used to determine, in an easy and rapid manner, the authenticity of the product so packaged. Preferably, such a method would be capable of being performed while the product is in a retail setting.